With the advent of air pollution requirements, it has been necessary to remove sulfur-containing gaseous contaminants from hot coal gasification effluent gases, some of which (e.g. SO.sub.2) have previously been expelled to the atmosphere. Other sulfur-containing gaseous contaminants such as hydrogen sulfides and other sulfides such as CS.sub.2 that are customarily found in such effluent gases, have also had to be removed not only because of corrosion problems they would induce but also because the oxides of sulfur formed during combustion would be a nuisance to coal gas consumers.
Heretofore, hot H.sub.2 S containing hot coal gasification gas mixtures have been purified by having had their H.sub.2 S content removed by conventional scrubbing, such as by wet or dry scrubbing, e.g., by caustic scrubbing. The dry method of scrubbing, now largely superseded by the wet method, consisted in the removal of sulfides such as H.sub.2 S through contact with dry iron oxide or hydroxide and subsequent extraction of the spent and reactivated hydroxide with carbon disulfide for recovery of the sulfur. On the other hand, wet scrubbing has simplified considerably the overall coal gas purification through scrubbing of the coal gas with various liquids, e.g. a caustic solution such as a dilute (3%) solution of sodium carbonate. Other wet methods have utilized dilute (1-2%) soda-ash solutions with ferric hydroxide suspended therein; aqueous arsenious oxide in soda ash; cold solutions of organic amines such as 50% aqueous solutions of diethanolamine; sodium phenolate comprising a fairly concentrated solution of phenol in caustic soda; etc. However, wet scrubbing has not proved to be entirely satisfactory since it often involves the need of costly specialized equipment such as absorbers, e.g. bubble-cap or packed absorption towers, heat exchangers, and the like. A significant advantage of the present invention lies in its ability to effect coal gas purification through removal of H.sub.2 S therefrom in a much simpler manner than heretofore afforded by the various scrubbing methods previously utilized. Thus, in accordance with this invention, the H.sub.2 S contamination of hot coal gasification effluent gases can readily be accomplished through use of a nickel-containing material or acceptor at elevated temperatures, thereby obviating the need for costly heat transfer equipment previously associated with scrubbing, which material or acceptor can easily be regenerated by oxidation, e.g. air oxidation.